Optical drawing device



35 0 -l 1 7 Search Hoon March 15, 1938. H- s, WCE 2,111,198

OPTICAL DRAWING DEVICE Filed March 18, 1935 2 Sheets-Sheet l A f E w l NVEN TOR.

2 5 Hkz/dd Stoddard l/icef ATTORNEY.

Search Hoo March 15, 1938. H s WCE 2,111,198

OPTICAL DRAWING DEVI CE Filed March 18, 1935 2 Sheets-Shea?I 2 l:Nm/rok. M rman Sfoddard Vice' BY Q A TTORNE Y.

Patented Mar. 15, 1938 Search Roer PATENT OFFICE QP'IICAL DRAWING DEVICEHerman Stoddard Vic, Chicago, lll.

Application March 18, 1935, Serial No. 11,573

6 Claims.

This invention relates to optical drawing devices, and the principalobject of the invention is to provide an optical member having a systemof mirrors or reflector plates adapted to be supported above a drawingboard, and arranged to reflect the image of the object (which is to becopied) through a sight opening to the eye of the user, so that whilelooking through the sight opening, the user sees the drawing paper withthe image of the object appearing as though superimposed thereon,whereby the user may readily trace or draw the image upon the drawingpaper.

Another object is to provide one of the reector plates with a lighttransmitting portion therein, whereby the eld viewed on the drawingpaper is visible around the light transmitting portion, and also toprovide another reflector plate having a reflecting surface,electrically or chemically deposited thereon, or otherwise appliedthereto in such manner as to provide a reflecting surface which ispartially transparent, whereby the user may look through the same andsee the drawing paper below, with the image of the object (reflected bysaid partially transparent reflector) having the appearance of beingsuperimposed upon the drawing paper.

In accordance with the present invention, the entire eld is visible, andthe user may trace any portion of the image and may shift his drawingtool from place to place on the drawing as is found most convenient incopying the object.

Another object is to provide swivel connections between the housing ofthe optical member and a standard, whereby to adjust lthe optical memberinto proper relation with respect to the drawing paper and object to becopied. Another object is to provide lens mounts and lenses inconnection with the reectors.

With these and other objects and advantages in view, this inventionconsists in the several novel features hereinafter fully set forth andclaimed.

The invention is clearly illustrated in the drawings accompanying thisspecification in which:

Fig. l is a side elevation of an optical drawing device embodying asimple form of the present invention and showing the same in positionfor copying an object upon a sheet of drawing paper;

Fig. 2 is a detail vertical longitudinal section through the opticalmember of the device;

Fig. 3 is a detail section taken on the line 3-4 of F18. 2;

Fig. 4 is a detail section taken on the line 4-4 of Fig. 2;

Fig. 5 is a side elevation of the device looking at the reverse sidefrom that seen in Fig. 1;

Fig. 6 is a front elevation of the device looking in the direction ofthe arrow 6 in Fig. 5;

Fig. 7 is a fragmental section taken on the line '|-1 of Fig. 5;

Fig. 8 is a plan of the device;

Fig. 9 is a detail horizontal cross section taken on the line 9 9 ofFig. 6, and

Fig. l0 is a detail vertical section taken on the line ||I||| of Flg. 6.

Referring to said drawings, the reference character A designates aVsupport and B the optical member of the device. The support comprises astandard 20 having a base or clamp 2| by which it may be mounted upon atable or drawing board 22. In accordance with the common practice, thedrawing board is supported in a slightly inclined position as is seen inFig. 1. The clamp shown is of the usual U shape having a clamp screw 23by which it is clamped to the drawing board. Desirably, the standard isextensible and contractable and as shown, is composed of telescopictubes 2l, 25, 26. The inner tube 25 has a tongue or lug 21 upon itslower end, which travels in a slot 28 formed in and extending lengthwiseof the outer tube 26, whereby to hold the telescopic tubes 25, 2Sagainst relative rotation. A set screw 29 threaded in a collar orenlargement formed on the tube 25 and adapted to bear against the tube24, and a split clamp collar 30 slidably mounted on the tube 26,together with a clamp screw 3| and wing nut 32 provide means for holdingthe telescopic tubes in any angular and lengthwise position ofadjustment. In practice, the clamp 2| is fastened at one edge of thedrawing board, and inasmuch as the optical member B should be directlyover the drawing paper upon which the drawing is to be made, thestandard is fulcrumed upon the clamp 2| to enable it to be tilted overthe drawing board, whereby to bring the optical member directly over thesame at any point desired. The standard is fulcrumed to the clamp by apin or screw 33 extending through ears on the clamp and through thelower end of the standard, and means, such as brace rods 34 are providedfor bracing the standard in any position of angular adjustment. Thebrace rods are fulcrumed upon an arm 2 of the clamp at a point distantfrom the fulcrum for the standard, and are connected to the clamp collar30 by the clamp screw 3| and wing nut 32. To adjust the standard, thewing nut is backed off slightly, the standard adjusted to properposition and the wing nut screwed up tight.

The optical member B is adjustably secured to the support A by swivelconnections which will now be described. Secured to and projectinglaterally from the tube 24 is a clip 35 formed with a pair of ears 36between which is an inverted U shaped clamp member 31 (see Fig. 10)containing a non-rotatable nut 38 in which is threadedly mounted a clampscrew 39 that extends through the ears 36 and the two forks of the Uclamp member 31. This arrangement provides means for adjusting theoptical member angularly in a vertical plane. A stud shaft or pin 40 towhich the optical member is fastened, is rotatively held in the U bendof the clamp member 31, whereby the optical member may be rotated on theaxis of the stud shaft or pin 40. A clamp nut 4I threaded on the clampscrew 39 and bearing against the side of one ear 36 of the clip 35provides means for tightening the U clamp member 31 upon the stud shaft40. In use, the optical member is adjusted upon its swivel connectionswith the standard to bring the axis of the sight opening into a lineperpendicular to the drawing board.

In its preferred form, the optical member B comprises a housing 42,mirrors or reflector plates 43, 44 therein and suitable mountings forlenses as will be hereinafter explained. The housing is swiveled on asupporting arm 45 to which the stud shaft 40 is attached, and said armis desirably provided with a blind mounting 46 spaced from thehereinafter mentioned lens mounting on the housing, a distancecorresponding to the distance between the eyes of a'human being.

The housing 42 has an opening at one end through which light rays enterthe housing and are reflected by the mirrors, and also has openings inits top and bottom walls through which the user views the image. Forconvenience in assembling the parts the housing comprises top and bottomsections detachably secured together. As shown the top section comprisesa top wall 41, side walls 48 and an end wall 41e. 'Ihe lower sectioncomprises an inclined bottom wall 49, an annular base 5U and upstandingwings or walls 52 that extend upward between and adjacent the side walls48 of the top section. A tongue 5| on the base 50 engages in a slot inthe end wall 41SL and tongues 5 I*l on the lower front corners of theside walls 48 lie in front of the front edges of the wings 52 and holdthe two sections together. The arm 45 has a ring like enlargement 45* onits end, and the annular base 50 is swiveled thereon by a flanged ring56.

The mirror or reflector plate 43 is held between the lower face of thetop wall 41 and the upper edges of the wings 52 and the mirror orreflector plate 44 is held between and supported by flanges 54 thatproject inwardly from the wings 52 and extend in an inclined direction.The lower end of the mirror 44 bears against a shoulder 55 at the upperend of the bottom wall 49.

The opening in the top wall 41 of the housing is covered by a centrallyapertured flanged cover 58 which slips upon an upstanding annular flange58a on the top wall 41. The aperture 59 of the cover, provides a sightopening in the housing through which the image reflected by the mirrorsis visible and through which the drawing paper below is visible. Ashoulder 60 is provided on the top wall of the housing below the cover58 to support a lens 6| which is confined thereon by the cover 58.Desirably a lens mounting ring 62 is swiveled upon the supporting arm 45in which may be placed a lens 63 which co-operates with the lens 6| toequalize the focal distances. A lens mounting 64, 65 for an enlarging orreducing lens 66 may be provided at the open end of the housing forenlarging or diminishing the size of the image reflected. The lenses arenot required, but they are provided for aiding persons who use eyeglasses and also for the purpose of enlarging or diminishing the size ofthe image of the object to be drawn.

The mirror or reflector plate 43 may comprise a plane mirror or othertransparent plate backed with silver or other reflecting material.Directly below or in line with the sight opening 59, the reflectingmaterial of the reflector plate 43 is omitted so as to leave a cleararea 68 whereby light rays may pass through the transparent area of themirror or reflector plate 43 to the eye of the user, so that a personlooking through the sight opening may see the image reflected by themirror or reflector plate 44.

The mirror or reflector plate 44 is coated on one side with a partlytransparent reflecting material 69, such as a very light fllm of silveror other suitable reflecting material, either electrically or chemicallydeposited on the transparent plate in such manner that the mirror servesto reflect images and also enables one to see through the film and Viewthe drawing below. The coating on the reflector 44 may be in the natureof a thin lm having the property of reflecting an image and beingsufllciently transparent to permit the drawing paper below it to be seenthrough it. A transparent plate 44l is adhesively secured to thereflector plate 44 on the side which contains the reflecting fllm andserves as a protection for the thin film.

The two mirrors or reflector plates 43, 44 are angularly disposed at anangle which gives the best results and I have found that such an angleis one of approximately 33 degrees. Rays of light entering through theend opening of the housing (as indicated by the broken lines a inFig. 1) are reflected by the upper mirror or reflector plate '43 uponthe lower mirror or reflector plate 44 and by the latter are reflectedback through the clear area 68 in the upper reflector plate to the eyeof the user, thereby producing an image of the object to be drawn, whichimage appears to be superimposed upon the drawing paper below, andinasmuch as the eye of the user sees the drawing paper below with theimage apparently superimposed thereon, and also sees the pencil or otherdrawing instrument used by him to copy the object, he can readily traceor draw the picture by following the lines, shades and shadows thatappear to be superimposed upon the drawing paper.

In use, the device is secured in place upon the drawing board and theoptical member is properly adjusted above the drawing paper, the objectto be copied being placed at a suitable distance away from the device.The user looks through the sight opening and traces, marks or draws inthe image reflected by the mirrors and which appears to be superimposedupon the drawing paper. The clear space on the upper reflector plateenables the user to obtain a view of the whole field upon the drawingboard and the transparent reflector plate enables the user to see theentire surface of the drawing paper. The parts are so co'nstructed andarranged that the device may be folded into compact form and placed in asuitable case. The transparent reflector plate 44 appears to betransparent throughout its entire area as distinguished from reflectorplates that Qdi have alternate transparent and reflecting portions. Inother words the transparency appears continuous throughout thereflector.

I claim as new and desire to secure by Letters Patent:

l. An optical drawing device, comprising a housing having a top, bottom,sides and one end wall, the other end being open, there being a sightopening in the top and a relatively large opening in the bottom,separated from the open end by a cross wall, a reflector plate in thehousing having a light transmitting portion therein aligned with thesight openings'in the housing, a transparent reflector plate in thehousing, angularly disposed with respect to the rst mentioned reflectorplate and having a thin transparent reflecting lm on one side thereofextending throughout its entire exent, whereby light rays may pass frombelow through said aligned openings, and a transparent plate secured onthe side of the transparent reilector plate containing the thin film,whereby to protect said lm, said first mentioned reector plate servingto reflect an image upon the second mentioned reflector plate, and thelatter serving to reflect the image through the sight opening in the topof the housing.

2. An optical drawing device, comprising a housing having a top, bottom,sides and one end wall, the other end being open, there being a sightopening in the top and a relatively large opening in the bottomseparated by a wall from the open end of the housing, a supporting armhaving a large opening therein at one end disposed coaxially with theopening in the bottom of the housing, the housing being swiveled on saidarm at the opening therein, a reflector plate in the housing disposedadjacent the top and having a light transmitting portion in line vwiththe openings in the top and bottom, and a transparent reector plate inthe housing angularly disposed with respect to the first mentionedreflector plate and extending across the opening in the bottom of thehousing.

3. An optical drawing device, comprising a housing having a top, bottom,sides and one end wall, the other end being open, and the top extendingforward beyond the bottom, there being a sight opening in the topadjacent the end wall and a relatively large opening in the bottomaligned with the sight opening and separated from the open front end bya wall, a lens mount on the top having a sight opening in line with theopenings in the top and bottom, and a lens mount under the opening inthe bottom, lenses removably heldin said lens mounts, a reflector platein the housing disposed adjacent the top and having a light transmittingportion in line with the aligned openings in the top and bottom, and atransparent reflector plate angularly disposed with respect to the firstmentioned reflector plate and extending across the opening in the bottomof the housing, both of said reflector plates being contained entirelywithin the housing.

4. An optical drawing device, comprising a housing composed of a toplens holder having an opening therein, a bottom lens holder having anopening parallel with and aligned with the opening in the top lensholder, lenses removably held in said lens holders, a top wall extendingfrom the top lens holder side walls and one end wall connecting saidlens holders, a reflector plate parallel with and supported underneaththe top wall of the housing, said reflector having a light transmittingportion in its reflecting surface in alignment with the openings in thetop and bottom lens holders, and a transparent reflector extending fromthe inner end of the first mentioned reflector and at an angle theretoacross the bottom opening, both of said reflector plates being containedentirely within the housing.

5. An optical drawing device, comprising a. housing having a top,bottom, sides and one end wall, the other end being open, and therebeing aligned sight openings in the top and bottom, a support connectedto the housing for supporting the same in spaced relation to a drawingboard, upper and lower angularly disposed reflector plates containedentirely within the housing and extending across said sight openings,the upper plate having a light transmitting portion aligned with thesight openings in the housing, and the lower reiiector plate beingtransparent, a lens removably mounted at the open end of the housing,and a lens at the lower sight opening.

6. An optical drawing device, comprising a housing having a top, bottom,sides and one end wall, the other end being open, there being a sightopening in the top and a relatively large opening in the bottom, upperand lower lens mounts adjacent said openings, and lenses removablymounted in said lens mounts, a plate mounted in said housing and havinga reflecting surface and having also a light transmitting portionaligned with the sight opening in the housing, a transparent platemounted in said housing in angular relation to the first mentioned plateand having a transparent reflecting surface throughout its entire extentthrough which light rays may pass from below,'to and through said lighttransmitting portion, the transparent reecting surface thereof servingto reiiect through said sight opening an image reflected by the rstmentioned reflector plate, and both of said plates being containedentirely within the housing.

HERMAN s'roDDARD vIc.

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